The present invention relates to stacker cranes.
Stacker cranes transport articles by moving a travel vehicle along a travel rail and raising and lowering a vertically movable platform on which an article is placed. In conventional configurations, the travel vehicle is constructed by connecting the lower end portions of a pair of front and rear support posts via a connection frame, and connecting a support frame that supports wheels and drive means to each of the front face of the front-side support post and the rear face of the rear-side support post, so that the lower end portions of the support posts are connected by and supported on the connecting frame and the support frames (see JP 2003-212308A, for example).
When the stacker crane is long in the fore-and-aft direction, the range over which it moves becomes wide, and thus although it is preferable for the stacker crane to have a short fore-and-aft length, it was not possible to narrow the gap between the pair of front and rear support posts more than a set spacing that corresponds to the width of the spacing between storage racks to which articles are transferred. Accordingly, in order to shorten the fore-and-aft length of the stacker crane, it is possible for the lower ends of the support posts to be connected by and supported on the forward end portion or the rear end portion of the travel vehicle so as to shorten the fore-and-aft length of the travel vehicle. In the conventional configuration described above, however, the support frames are connected to the front face of the front support frame and to the rear face of the rear support frame, and the support frames and all of the drive means and travel wheels supported on the support frames are positioned either in front of or behind the support posts. This causes the front end portion and the rear end portion of the travel vehicle to project significantly outward from the positions where the support posts are supported and thus increases the fore-and-aft length of the travel vehicle and makes it difficult to shorten the fore-and-aft length of the stacker crane.